Traditional telephony services provided by digital switches, such as digital multiplexing switches, have reached their functional limits with existing user interfaces, which essentially are telephone sets having limited displays and simple keypads. Further, the telephone sets have limited bandwidth. Over newer packet networks, multimedia services are flourishing and are capable of exploiting the capabilities of advanced user terminals, desktop computers, and network appliances.
Currently, the vast majority of voice telephony is provided, at least in part, by traditional circuit-switched networks. Given the extensive infrastructure, reliability, and quality of service, the traditional telephony systems are likely to remain a significant part of communications for the foreseeable future. Unfortunately, there has been difficulty integrating voice sessions over the traditional telephony network with multimedia sessions over packet networks. Users prefer the traditional telephony network for voice, yet the voice network is unacceptable for facilitating advanced multimedia services, such as screen sharing, video conferencing, and the like.
In addition to the difficulties of integrating the voice and multimedia sessions, integrating services that heretofore were available on voice systems is proving problematic. For example, several years ago, a voice service was introduced which allowed two extensions to share a number such that if a call came in, the phone at both locations would ring, calls could be put on hold at one phone and picked up at the other, or other similar sorts of activities. This was particularly useful for boss-secretary arrangements.
While the problem of porting this functionality over to a packet based network has been solved, there remains a need to exploit the full force and power of multimedia services in combination with this call coverage functionality.